Method and device for producing three-dimensional models

ABSTRACT

The present invention relates to a method for producing three-dimensional objects based on computer-provided data, whereby a material is deposited in layers in a process chamber and the material is selectively solidified and/or bonded using a bonding apparatus and/or a solidifying apparatus in the process chamber, these steps being repeated. A conveyance of the material proceeds during the build process and proceeds continuously, sequentially and evenly up to an unpacking position.

The invention relates to a method for manufacturing three-dimensionalmodels as expressed in the generic concept of patent claims 1 and 14 aswell as a device as expressed in the generic concept of patent claim 16.

A method for producing three-dimensional objects from computer data isknown from the prior art, for example, from the European patentspecification EP 0 431 924 B1. In the method described therein, aparticulate material is deposited in a thin layer onto a platform, and abinder material is selectively printed on the particulate material,using a print head. The particle area onto which the binder is printedsticks together and solidifies under the influence of the binder and, ifnecessary, an additional hardener. The platform is then lowered by adistance of one layer thickness into a build cylinder and provided witha new layer of particulate material, which is also printed as describedabove. These steps are repeated until a certain, desired height of theobject is achieved. A three-dimensional object is thereby produced fromthe printed and solidified areas of the particulate material.

After it is completed, this object produced from solidified particulatematerial is embedded in loose particulate material and is subsequentlyremoved from the process chamber and freed from loose particulatematerial. This is done, for example, using an extractor. This leaves thedesired objects, from which the remaining particulate material isremoved, e.g. by brushing.

Other particulate material-supported rapid prototyping processes work ina similar manner, such as, for example, selective laser sintering orelectron beam sintering, in which a loose particulate material is alsodeposited in layers and selectively solidified with the aid of acontrolled physical radiation source.

All these methods are referred to collectively below as“three-dimensional printing methods” or “3D printing methods”.

All the mentioned embodiments have in common a detailed manufacturingprocess for the desired products. The first step always consists ofgenerating a filled volume, which contains the components, in theaforementioned process chamber. An example could be a powder feedstock.Further individual sequentially ordered steps follow, such as theremoval of particulate material in order to obtain the desired finalcomponents.

In various further publications, such as patents WO2004014637A1 or U.S.Pat. No. 7,291,002B2, at least the build process is considered and acontinuous operation for this purpose is suggested. Included in such isthat the build platform is continuously lowered and the layerapplication is implemented in a screwing movement over the build area.However, in addition to the high equipment costs, also with this method,only one step is completed after termination of the build process. Theremoval of the unbound particulate material proceeds again in asubsequent, separate process.

The object of the invention is to provide a method and a device withwhich it is possible to continuously carry out diverse work steps.

This object is achieved by a method according to patent claims 1 and 14as well as a device according to patent claim 16.

According to one aspect of the present invention is a method forproducing three-dimensional objects, using a three-dimensional printingmethod based on computer-provided data, whereby a material is depositedin layers in a process chamber and the material is selectivelysolidified and/or bonded using a bonding apparatus and/or asolidification apparatus in the process chamber, these steps beingrepeated.

In hereby doing so, a conveyance of the first material proceeds duringthe build process and proceeds continuously sequentially and uniformlyup to an unpacking position. Whereby “continuous” according to theinvention does not mean that the conveyance always takes place with thesame speed. Depending on the design, the conveyance can also proceed insteps.

The first material can include any imaginable material that can bedeposited layerwise. This could be e.g. a powder material, a filmmaterial or a fluid material, for example a melted extrusion and/or adripped material as used with the known Fused Deposition Modeling (FDM)process.

If a particulate material is now provided as a first material, then,according to a preferred embodiment of the present invention, a methodfor producing three-dimensional objects could be provided that uses athree-dimensional printing method based on computer-provided data,whereby a material is deposited in layers with the aid of a spreaderdevice in a process chamber onto a particulate material feedstock andthe particulate material is selectively solidified using asolidification apparatus in the process chamber, these steps beingrepeated until a desired object is obtained and unpacked.

According to a preferred embodiment of the present invention, the buildprocess includes the application of a first material layer and, ifrequired, the solidification of certain areas, according to the computerdata provided.

The conveyance of the first material continuously, sequentially anduniformly up to an unpacking position including during the build processenables the continuous and to some degree simultaneous implementation ofmultiple work steps. Such a device can also be operated infinitely.

Whereby conveyance, according to a preferred embodiment of the presentinvention, does not mean only the execution of a first material. Itcould also well be that the spreader unit and the solidification unitare moved over the layers of the first material and, consequently, anarea of a process chamber or build-up space and with it also anunpacking position is constantly shifted and thereby the first materialis conveyed according to kinematic reversal.

It is thus proposed to dispense with a lowerable build platform duringoperation of the method and instead of this to produce a continuousmaterial layer stack or even a particulate material feedstock, forexample. This material layer stack or particulate material feedstockwith built objects, if applicable, can on one side have already exited aprocess space as well as the unpacking position, while on the other sidethe build process of objects is still being executed.

According to a preferred embodiment of the invention, in a methodaccording to the invention, a conveyance direction essentially remainsup to the unpacking position. According to the invention, this should beunderstood to mean that the conveyance may well exhibit slight directionchanges, such as curves. However, no direction reversal is to takeplace. Since the conveyance process is continuous, the conveyance speedalso remains essentially the same.

According to a preferred embodiment of the invention, it may proveadvantageous if the spreader device, respectively the means forapplication for the first material, and a deposited material layer ofthe first material are such provided that the means for application andsaid material layer are moved toward each other relatively for saidapplication of a further material layer that a reception plane of thematerial layer exhibits an angle of >0° to a layer plane of the meansfor application.

The use of particulate material could e.g. include such that thespreader device and the particulate material feedstock are such providedthat said spreader device and feedstock are moved toward each otherrelatively for application of a further material layer that a receptionplane of a particulate material reception means exhibits an angle of >0°to a layer plane of the spreader device.

Especially preferred is the selection of an angle less than or equal toan angle of repose of the particulate material.

Depending on the method and manner in which the material is movedforward, it may be helpful under circumstances if the solidificationapparatus creates structures in the material, especially auxiliarystructures, which hamper the sliding away of material in the processspace. Such an embodiment can yet further stabilize the material layers.

When using particulate material, the method according to the inventioncan preferably be executed in such a way that first particulate materialis introduced in a feedstock in a process chamber and then a buildprocess of an object begins on this particulate material feedstock.

According to an especially preferred embodiment of the presentinvention, it may be provided that after removal from the process space,the objects created are e.g. unpacked from the particulate materialwithout interrupting the build process.

According to an especially preferred embodiment of the method accordingto the invention, solid material is deposited in the form of thin films.

These films can, for example, be connected to each other by means ofglueing and/or welding.

Besides that, it is also possible that the solidification apparatuscreates structures that facilitate the automatic unpacking of thecomponents.

By so doing, the method according to the invention can be executedcontinuously. That means that a build process of the object takes placein the layers of the material in a process space or process area and thematerial layers are always transported with the objects and the buildprocess can be carried out infinitely. After conducting the objects outfrom the process space area, these can be e.g. unpacked and removed fromany conveyance means if the material is moved according to a preferredembodiment via a conveyance means. In this regard, conveyance canproceed either continuously and/or discontinuously.

For example, it is conceivable that the conveyance runs ad infinitum.

It is also possible that the material moves horizontally or horizontallywith an angle.

According to a further aspect, the invention also relates to a methodfor continuously producing three-dimensional objects usingcomputer-provided data, whereby a material is deposited on a movablematerial reception means and on one side of the material an object ormultiple objects are formed by repeated application of layers of thematerial and subsequent solidification and/or binding of the materialand repetition of these steps, the object or objects on the materialreception means are continuously moved out of a process area during theproduction process and unpacked on the material reception means duringthe production process.

It may prove advantageous if the layer plane exhibits an angle of >0° toa reception plane of the reception means.

According to a further aspect of the present invention, a device forproducing three-dimensional objects using computer-provided data isdescribed, whereby a material is deposited in layers using a spreaderdevice and selectively solidified using a solidification apparatus andthese steps are repeated.

If, for instance, particulate material is used as the layer material,then it may be provided that such a device deposits particulate materialin layers with the aid of a spreader device on a particulate materialfeedstock and the particulate material is selectively solidified using asolidification apparatus and these steps are repeated.

To do so, means are provided to convey the material during the buildprocess continuously and sequentially up to an unpacking position.

Moreover, it is conceivable that the material includes film material,extrusion material and/or a fluid.

Preferably, it may also be provided that the solidification apparatuscan be a drop generator and/or a radiation source.

In this regard, a second material can be self-curing, for example, whencoming in contact with the particulate material. Or the particulatematerial can be mixed with a substance that leads to the solidificationof the material upon contact. It is also conceivable that the secondmaterial cures by means of UV radiation or supply of heat or in thepresence of a gas.

According to a further preferred embodiment of the present invention,the spreader device and/or the solidification apparatus are moved on acoordinate system arranged at an angle perpendicular to the receptionplane of the reception means.

If a particulate material is used, then preferably the angle selectedfor the coordinate system is smaller than the angle of repose of theparticulate material.

In so doing, according to an especially preferred embodiment of thepresent invention, the angle of the feedstock favors freeing the objectsafter the build process by means of sliding off of particulate material.

According to a preferred embodiment of the present invention, thematerial is moved on a conveyor, whereby this may advantageously haveone or multiple conveyor belts.

Furthermore it also possible that the conveyor has a chain conveyor.

In order to design the device somewhat smaller, it can also be providedthat it is provided with limitations of the material layers.

In this regard and if needed, these material layers can be stabilized bymeans of limitation walls on both sides as well as above.

On the front sides, the layer material or the feedstock (if usingparticulate material) are respectively accessible. A spreader devicethat deposits new particulate material onto the feedstock is mounted onthe one front side. To do so, the spreader device moves over thefeedstock at the angle alpha to the horizontal, which is less than theangle of repose of the particulate material. It is thereby ensured thatthe layer of newly deposited particulate material remains at the desiredsite and does not slip off. The angle alpha can advantageously beadjusted on the device in order to harmonize this to the particulatematerial. In addition, on this side a device is mounted that selectivelysolidifies the particulate material alongside the particulate materialplane defined by the spreader device. This solidification apparatus canbe a print head, which releases small fluid droplets on the particulatematerial with the result that the particulate material solidifies therein a locally demarcated manner. Other devices can alternatively beemployed, such as a radiation source for high energy beams.

After completion of a layer comprised of a coating and subsequentsolidification, the feedstock is further transported a distancedetermined by the layer thickness. This can proceed with the aid of aconveyor belt on which the feedstock rests.

It would be possible to also design the bordering surfaces on the sidesof the feedstock as synchronous conveyor belts. Examples of otherconveyance options include the use of form-fitting conveyor chains,which only partially engage with the feedstock, e.g. via adapters, andmove these forward layer thickness by layer thickness.

Subsequent to completion of the current layer and after the print headand spreader device have moved into a park position, it is alsoconceivable that an assembly line tray be used that comes in contactwith the feedstock and pushes it forward layer thickness by layerthickness in the direction of the other free end.

In all its described embodiments, a device according to the invention issimpler to construct than the described state of technology. This is dueto several points. On the one hand, the quantity of moving particulatematerial during continuous operation is nearly constant and does notincrease as is the case with devices of the prior art. That simplifiesguideways and drives since these can be designed for a constantoperating point. On the other hand, the movement of the particulatematerial feedstock and the reception of the forces of its own weightthat it exerts are separate from one another. The feedstock rests on anunderlay and does not have to be moved in the gravitational direction atall or only to a small degree.

To prevent slipping down of the feedstock, a grid structure can beprinted along with it. This stabilizes the particulate materialfeedstock and also helps to hinder the uncontrolled discharge of theparticulate material in the break-out zone later on.

The length of the feedstock from the printing and/or coating unit rightup to the exiting from the process space, respectively, the exiting fromthe process space and arrival in the unpacking area, for instance at aside opposite the process space, can be adapted to the respectivesolidification process. The length can be designed in a way that thefeedstock remains a certain retention period in a contiguous situationto e.g. give the liquid time to react with the particulate material,thereby developing adequate stability. It is also possible that thesolidification process requires heat or produces heat. Heat could beintroduced by e.g. a pre-heated particulate material or e.g. radiationsources, which warm the coating plane in which the feedstock is to beintroduced. In this case, the retention period can be used to allow thefeedstock to cool down in a controlled fashion from the side oppositethe solidification zone. There are also conceivable cases where botheffects are jointly used. In both cases, a gradient results thatconforms to the layer-building and passes through the feedstock.

In contrast to the discontinuous methods, in this case the layers reachthe break-out zone in the same sequence as they were built. Theretention period can thus be held nearly constant in the particulatematerial feedstock for all areas. This is a great advantage since inthis way the curing can proceed in a much more controlled manner and isthereby accompanied by less delay than with devices according to thestate of technology.

At the second free end, a break-out zone (unpacking position) isconnected, in which unbound parts of the particulate material areremoved. This can proceed manually or e.g. automatically with suctioningand/or blowing off. In so doing, the break-out zone should bedimensioned long enough in the layer-building direction that also largerobjects can be completely removed and that interruptions in break-outactivities even lasting longer periods of time do not necessarily haveto lead to a termination of the layer building process simply becausethe feedstock reaches the end of the device.

Since the components can be laid stacked over one another in thedirection of gravity, it may be required to embed the components withsupport structures that also have to be built and that are able todevelop sufficient backing effect even in the absence of surroundingparticulate material and to hold the components in position until theyare removed.

Moreover, the break-out zone can be designed in such a manner that agreat deal of the unbound particulate material can flow off freely. Forexample, this can take the form of a perforated underlay and/or may beachieved alone due to the absence of the lateral limitation walls.

The break-out zone can have auxiliary means such as nozzles pressurizedwith compressed air or other fluids, which are aimed at the particulatematerial feedstock and support the conveying away of unbound particulatematerial during operation. The discharge of particulate material in thebreak-out zone can also be supported by input of mechanical energy, suchas vibrations, for example.

If the particulate material is reusable in the process, then it can becollected in the break-out zone and again fed into the applicationprocess after a possible pass through a preparation section. In thepreparation section, it may also be necessary to perform a sifting ofthe particulate material and/or a regulated feed-in of fresh particulatematerial.

In this case, the device has the advantage over the state of technologyin that the application zone and the break-out zone are both present andunited in a single device and the material flows can thus be executedand controlled easily. Due to the continuous operation, only arelatively small quantity of particulate material needs to be bufferedif the corresponding particulate material is reused. If reusability ofparticulate material is completely implemented, then only a particulatematerial quantity corresponding to that of the solidified quantity needsto be supplied to the process.

In the case of horizontal orientation of the conveyance plane, thesolidification period, respectively, the break-out period only affectsthe length of the device.

However, the coordinate system of the layer building is not Cartesian,but rather distorted by the angle of repose.

In cases of a very small angle of repose of the particulate material,this can lead to highly distorted building spaces, respectively, processchambers, which in turn can lead to prolongation of the process durationrequired per component. It can therefore make sense to tilt theconveyance plane at a beta angle in relation to the horizontal and, byso doing, correctly reset the coordinate system. This has the additionaladvantage that the feedstock's own weight acts in the conveyancedirection and thereby reduces the force required to move the feedstock.

In this case, the angle of repose in the break-out zone acts against thegradient conveyance plane. This means that the particulate materialtends to flow out of the solidification zone. In the worst case, whenthe angle of repose is the same as the beta angle, the solidificationzone will completely flow out if no countermeasures are taken, such asprovision of printed compartments or a grid or honeycomb structure.

In both cases, it is necessary to set an auxiliary plate on theconveyance plane when starting the system, which enables the applicationof the first layers. This auxiliary plate takes over the alpha angle ofrepose and is pulled through the solidification zone by the conveyoruntil the end of the break-out space is reached and the auxiliary platecan be easily removed.

No special measures need to be observed, however, when shutting down thesystem. The free end of the feedstock is simply pulled through thesolidification zone into the break-out area.

Such a system enables the processing of a multitude of differentmaterials. Besides fluids, film material and extrusion material,possible materials also include sand, gypsum, metal particulate materialor other inorganic particulate materials as well as plastic particulatematerial, flour and other organic particulate materials.

The system and the process permit a wide spectrum of variedapplications, such as e.g. the manufacture of molds and models for metalcasting as well as the production of components of the most diversetypes. Likewise, an interesting advantage is that the continuousprocedure also allows production of longer components without having tomodify the device.

In general, its basic principle of essentially running horizontally inthe “Z-axis” makes it suitable for all solid processing layer processes.That means that the principle can function anywhere where the depositedmaterial has already developed sufficient stability shortly afterapplication so that it does not slide away sideways due to its ownweight.

According to the present invention, the material application types canvary.

Solid materials in the form of thin films made of paper, metal as wellas plastic etc. can be applied in layers (LOM). For example, they can beapplied to a layer body, which is essentially moved horizontally.

-   -   a. The application plane of the layer body can be positioned at        an angle of less than 90° to the movement direction, but this is        not obligatory. A Cartesian coordinate system would make sense        in such a case, meaning that the application plane is situated        perpendicular to the movement direction.    -   b. The films are applied onto the layer body and thereupon        connected e.g. by glueing, welding or similar means. The contour        of the component is cut out of the respective layer by means of        e.g. a laser, cutter assembly or other cutting method. In doing        such, the cutting can either take place before or after the        application step. If it takes place after the application step,        then the depth of the cut must be checked. To facilitate        unpacking, auxiliary cutting aids can be employed to divide the        surrounding film material into smaller units. The auxiliary cuts        can, for example, be executed in the shape of rectangles. On        complicated structures, the rectangles can be further reduced in        size in order to better access the contour. Another option for        simplification of unpacking is the selective application of        adhesive between the films. For example, this can proceed via        the photoelectric application of a hot melt adhesive (by means        of a laser printer).    -   c. The films can either be dispensed from the roll or        transported from a single-sheet supply in the application area.        Unrolling from the roll is advantageous in this context since        the automation expenditure can be kept minimal.    -   d. If the current film is applied and cut, then the infeed is        activated and the layer body is further transported by one layer        thickness. The layer body should have reached a certain length        in order to stably store the components located there. If the        layer body has reached this minimum length on the conveyor, then        removal of the excess film can be begun on the end opposite the        film application plane in order to break out the actual        components. The removal can then proceed manually. The advantage        of this build-up type lies in the quasi-infinite operation of        the system.    -   e. In order to start up the system, an additional device in the        form of an angle is needed upon which the first layers are        applied. The angle is needed until the layer body being built up        with layers acquires sufficient inherent strength that it can        bear its own weight without deforming.

Hot-melt materials can also be applied to the layer bodies in extrudedform (FDM). Likewise in this case, to start up the system an angle onthe conveyor is needed as an auxiliary platform until the layer bodyachieves sufficient stability. For this purpose, an extruded “rope” of ameltable material is conveyed via any one of the position-adjustableheated nozzles in the application plane so that a controlled materialflow of the now molten material is created at its outlet. The nozzle iscomputer-controlled over the existing layer body and selectivelydispenses material onto the corresponding areas. The material flow mustbe coordinated with the nozzle movement in order to guarantee a uniformextrusion thickness. The underlying structure made out of extrusionmaterial will melt again during application and will result in a solidconnection together with the new material. The nozzle movement iscontrolled via e.g. a system of two crossed spindle axes in the layerapplication plane.

-   -   a. So that components of any complexity can be created, a second        material is applied in the same manner via a second nozzle to        the areas that are suitable for supporting the weight of the        desired structure on the conveyance plane. The second material        can e.g. possess a lower melting point than the first material        or e.g. have different solubility characteristics in fluid        media.    -   b. In order to avoid delay, the layer body can be built in a        heated atmosphere. The temperature of the layer body, however,        should lie below the solidification temperature of the second        material.    -   c. The build-up of the layer body then proceeds in a manner        compliant to the method described under 1). After a certain        minimum length, the layer body can be conducted out of the        heated atmosphere via a cool-down section and, for example,        exposed to the dissolving fluid in a removal area, thus        separating the components from the support structures.    -   d. It is likewise feasible to isolate the layer body after        exiting from the cool-down section, e.g. via separation by means        of a thermo saw, and then further process the resulting blocks.        The blocks should then have the lengths of the intended        components located therein.

Not least of all, a layer body can also be created in a similar mannervia drip application of a second material (MM). To do so, print headsthat can generate individual drops of two different materials are movedin one layer application plane over the layer body and dispense thebuild material and support material corresponding to the contour dataissued by the computer. The support material must again ensure that atleast the layer body's own weight can be supported on the conveyanceunit.

-   -   a. Solidification of the build material can take place thermally        via cooling of a molten mass or likewise via a polymerization        reaction, e.g. by means of exposure to light of a        photo-sensitive polymer.    -   b. The same applies to the support material.    -   c. In all three cases, the control of the thickness of the layer        currently being processed represents the real challenge. In case        1), this cannot be adjusted since the thickness is determined by        the film used. It is therefore advisable to measure the glued-on        material thickness. The measurement can be used to calculate a        correction of the forthcoming layer data and to compensate for        previously resulting errors.    -   d. In cases 2) and 3), the application height can be checked by        means of an additional leveling element, such as the surface of        the nozzle in 2) or a heated roller or a scraper blade or a        cutter.

A method according to the invention can be implemented more simply thana method on devices of the state of technology.

In contrast to devices according to the state of technology, themovement of the device for layer positioning must not proceed rapidlybecause positioning runs with long paths are no longer needed. Aconsequence of such is that a discontinuous switching device may also beused. This involves moving one layer thickness after a spreadingprocess. One example could be a pneumatic actuator. The layer thicknessis controlled by means of end stops. Levers or gears can be used totranslate the movement. Especially preferred is an indexing clutch incombination with a lever that is actuated by means of a pneumaticcylinder.

For the purpose of more detailed explanation, the invention is describedin further detail below on the basis of preferred embodiments withreference to the drawing.

IN THE DRAWING

FIG. 1 An isometric view of a device according to the state oftechnology;

FIG. 2 A sectional view of a device according to the state oftechnology;

FIG. 3 A sectional view of a build chamber according to the state oftechnology and an illustration of various component stabilities;

FIG. 4 A sectional view of a preferred embodiment of the invention;

FIG. 5 An illustration on the angle of repose and the transference to apreferred embodiment of the invention;

FIG. 6 An isometric view of one preferred embodiment of the invention;

FIG. 7 A sectional view of a further preferred embodiment of theinvention;

FIG. 8 An illustration of possible error sources of devices according tothe invention;

FIG. 9 A sectional view of a preferred embodiment of the invention;

FIG. 10 A sectional view of a further preferred embodiment of theinvention;

FIG. 11 A sectional view of a further preferred embodiment of theinvention for the automatic unpacking of the components;

FIG. 12 An isometric view of a device according to the invention for theautomatic removal of particulate material;

FIG. 13 A sectional view of a device according to the invention;

FIG. 14 A plate link belt as conveyance means for the usage according toa preferred embodiment of the invention;

FIG. 15 A magazine belt as conveyance means for the usage according to apreferred embodiment of the invention;

FIG. 16 A perspective view of a method according to a preferredembodiment, which uses film as material;

FIG. 17 A perspective view of a method according to a preferredembodiment, which uses melted plastic as material;

FIG. 18 A perspective view of a method according to a preferredembodiment, which uses a print head to apply build material;

FIG. 19 A drive for layer positioning; and

FIG. 20 A chain-connected extended drive in conjunction with FIG. 19.

FIG. 1 shows a device according to the state of technology. A spreaderdevice (2) applies a layer consisting of particulate material on a buildplatform (3). At the conclusion, with the aid of computer-provided data,the particulate material is selectively solidified to a component (4)using the solidification apparatus (1), in this case a print head. Thevertical direction or also the direction of gravity, which is depictedhere perpendicular to the build platform (3), is designated with arrow(5). After solidification the build platform (3) is lowered by one layerthickness and then another layer is created.

In FIG. 2 the same device is depicted in sectional view. Several layershave already been created. A limiting factor during the method accordingto the state of technology is the build chamber depicted in the figureas (7), which is in this case also the process chamber. After a certainbuild height (6), the chamber (7) must be emptied or exchanged.

If the solidification is not immediately effected, but rather with acertain time delay, then special circumstances are to be taken intoconsideration with the method according to the state of technology.

As an example that can be derived from FIG. 3, during unpacking ofcomponent (4), the parts that were last created by the solidificationapparatus (1) and the spreader device (2) are located above in the buildchamber (7). These parts (8) are less solid than the parts (9) and (10)located further below in the build chamber (7). This necessitates aminimum waiting time that must be complied with before unpacking duringsuch a process.

FIG. 4 depicts the first of the preferred embodiments of the invention.FIG. 4 shows a sectional view comparable with FIG. 2. The methodsequence is subdivided into sub-steps, namely, commissioning of thedevice, continuous production of components (4) and shutdown of thedevice. These phases are described in the following:

Commissioning:

Creation of a basic feedstock—The spreader device (2) applies one layercomparable to that shown in FIG. 1. The layer plane of the particulatematerial, however, which, with the state of technology, corresponds to aplane that is parallel to the build platform (3), is inclined at anangle α in relation to a conveyor belt (11) here.

This coating process is repeated until sufficient filling is present toobtain the desired dimensions for component (4) being manufactured. Inthis manner a feedstock results, which is smooth on the spreader deviceside and fissured on the opposite-facing side in accordance with theparticulate material properties.

Continuous build process:

If a basic feedstock is created, then a continuous build process canbegin that only requires termination when the device is stopped formaintenance purposes. The process is designed to a great degree alongthe lines of the state of technology.

In a process chamber the spreader device (2) creates a layer that formsan angle α in relation to the perpendicular (5). At the conclusion, apredetermined quantity of particulate material is selectively solidifiedusing the solidification apparatus (1). The process chamber is in thissense not a delineated room, but rather the space in which the object isbuilt; the object is subsequently removed from this area, respectivelyprocess chamber.

The computer data processing must take this arrangement intoconsideration. The conveyor belt (11) is thereafter moved one layerthickness further so that the feedstock moves out from the spreaderdevice plane and hereby gradually moves out of the process chamber. Thisprocess repeats itself until the device is shut down. Located in thefeedstock are the components (4), which are ever further removed fromthe spreader device plane by the infeed movement.

After a certain distance on the conveyor belt (11), the components canbe unpacked, while the build process continues uninterrupted in theprocess chamber. The length of this distance of the conveyor belt (11)hereby depends on the process employed. For instance, cooling isrelevant when dealing with sintering processes. The curing time isrelevant in cases of chemical solidification mechanisms.

In addition, the ejection of components (4) and the unbound particulatematerial from special areas may proceed in this area, such as, forexample, protective gas atmospheres.

The unpacking itself can take place manually on the device or viadischarge of the particulate material.

Shutting Down:

If the device is to be shut down for maintenance purposes, the entirefeedstock can be brought on the conveyor belt (11) and out of theprocess chamber by moving the conveyor belt (11).

The angle (13) between the conveyor belt (11) and the spreader deviceplane is limited by the angle of repose of the particulate material(FIG. 5). Since an angle greater than the angle of repose (12) isaccompanied by an increased risk of particulate material sliding off,the angle selected should be smaller than the angle of repose (12). Inso doing, it can be guaranteed that a perfect surface is alwaysavailable for the build process.

FIG. 6 shows an isometric view of an especially preferred embodiment ofthe invention. Here can be seen the walls (14) mounted for lateraldelimitation of the feedstock. The feedstock runs through and issubjected to frictional forces. These walls enable the device, at thesame usable cross-section, to be built smaller than if the particulatematerial were allowed to laterally flow freely. Outside of the processchamber, the walls (14) can be dispensed with so that a portion of thework required for unpacking the components, namely removal of unboundparticle material, can be carried out by allowing the particulatematerial to freely run off (15) by simply leaving these walls (14)absent.

FIG. 7 shows another preferred embodiment of the invention. Theillustration shows a sectional view. The conveyor belt (11) is inclinedat a certain angle in relation to the perpendicular (5) here. Viewedhorizontally, the plane on which the spreader device (2) and thesolidification apparatus move now lies flatter than with the initiallydescribed device. On such an embodiment of the invention, particulatematerials that exhibit a shallower angle of repose can also beeconomically processed. The steeper angle in the unpacking area does notdisturb because a smooth surface area is not required here. The anglealso favors the self-actuating unpacking of components (4).

If the angle of repose (12) is exceeded by the device according to theinvention, then the smooth surfaces in the particulate material areas(18) created by the spreader device (2) break out so that no definedsurfaces exist any longer for the solidification process. One method toaddress this problem is described in the following:

Another preferred embodiment of the invention is shown in FIG. 9.Protective structures or auxiliary structures (19) are created via thesolidification apparatus (1). These artificially increase the angle ofrepose (12) of the particulate material. By so doing, “difficult”particulate materials can also be processed without modification of thedevice. The horizontal surfaces shown can be used for this purpose.However, there is no limit placed on usage of other structures, whichcould exhibit nearly any three-dimensional structure.

FIG. 10 shows the above-described devices with the same correspondingarrangement. In this case, the material extrudate is discharged parallelto the perpendicular. So that the feedstock created by the spreaderdevice (2) does not slip away, plates, represented by floor plates (20),are built by the solidification apparatus (1). These engage with atleast two conveyor belts. The remaining walls can be implemented rigidlyfor delimitation of the particulate material feedstock. Shown below theactual device is another transfer conveyor belt (22) that enables acontinuous production process as described in claim 1. The feedstock istaken over here and the components (4) can be removed as the devicecontinues to produce.

The described continuous production principle is also suitable for theconstruction of an entirely automated production system. This isrepresented in FIG. 11. In order to enable a robot (24) to grip thecomponents (4), the option exists to attach auxiliary structures (23)with the solidification apparatus, thus facilitating grasping by therobot (24). The position of the components (4) in the feedstock is knownfrom the production principle and can be used for the control of therobot (24).

FIG. 12 shows a preferred embodiment of a conveyor belt (11) to move thefeedstock. The conveyor belt (11) itself contains openings (26). Beneaththe conveyor belt (11) is a guidance plate (25). This bears the weightof the feedstock and guarantees the accuracy of feedstock movement. Theguidance plate (25) has no openings in the area in which the feedstockis created and in the area in which components (4) are subsequentlysolidified. In the unpacking area, the openings (26) and (27) corresponddepending on the position of the belt (11). A portion of the particulatematerial thus runs off by itself and exposes the components (4).

FIG. 13 shows that with a device according to the invention evencomponents (4) that have very large sizes in one dimension can beproduced. Such components must merely be supported if they are longerthan the actual size of the device. To this end, additional simpleconveyor belts (28) can be provided that take over the component orcomponents (4) at the end of the device.

Further conveyance means are depicted in FIGS. 14 and 15, showing howaccording to the invention they could be used instead of a conveyorbelt.

A plate-link belt is shown as a conveyance means in FIG. 14, while FIG.15 shows a magazine belt. Plate-link belts have proven to beadvantageous conveyance means since they can receive heavier loads thane.g. fabric-based belt conveyors and they additionally exhibit greaterrigidity perpendicular to the conveyance direction. In FIG. 14, twovarious plate-link belts are depicted, which have linked plates (29).The build space (7) could be provided with such conveyance means forobjects e.g. in the dashed line area.

The use of magazine belts (see FIG. 15) in a device according to theinvention proves advantageous if, in addition to high rigidity,modularity is also required in the conveyor chain. With the aid of suchmagazine belts, e.g. printed objects can remain on the respectivesection of the conveyor line, for instance, on the build platform (31),until further use in a magazine (32) after completion of the build-upprocess and in this manner be separated temporarily from the remainingconveyor chain. The conveyor length can also be relatively freelyadapted to the requirements and local conditions by simply either addingadditional link plates (31) in the magazine (32) or removing them fromthere. This can take place e.g. using a cylinder (30), which pushes alink plate out of the magazine and then moves this forward over theconveyor rollers (33). One possible arrangement of a build space (7) isshown again as a dashed line drawing.

FIG. 16 shows a method according to a preferred embodiment of theinvention. In this case, this is an endlessly continuous process forgenerative manufacturing methods, in which film layers (34) with cut-outcontours are glued to a model (35).

The film layers can be thin rolls (38) made of paper, metal as well asof plastic. They are applied on a workpiece being run (36), which ismoved essentially horizontally on a conveyor belt (11).

The application plane of the layer body proceeds with an angle less than90° in relation to the movement direction.

The films (34) are applied onto the layer body and thereupon connectedby means of e.g. glueing, welding or similar means. The contour of thecomponent is cut out of the respective layer e.g. with a laser (37). Thecutting can either take place before or after the application step. Ifit takes place after the application step, then the depth of the cutmust be checked. To facilitate unpacking, the aid of a hot-wire saw (39)can be employed for auxiliary cuts, which divide the surrounding filmmaterial into smaller units. The auxiliary cuts can, for example, beexecuted in the shape of rectangles. On complicated structures, therectangles can be further reduced in size in order to better access thecontour.

If the current film layer (34) is applied and cut, then the infeed isactuated and the layer bodies are further transported by one layerthickness. The layer body should have reached a certain length in orderto stably store the components or models (35) located there. If thelayer body has reached this minimum length in the conveyor direction(11), then removal of the excess film can be begun on the end oppositethe film application plane in order to break out the actual components.The removal can then proceed manually. The advantage of this build-uptype lies in the quasi-infinite operation of the system.

In order to start up the system, an angle or workpiece (36) is neededupon which the first layers (34) are applied. The angle is needed untilthe layer body (35) being built up with layers acquires sufficientinherent strength and can bear its own weight without deforming.

FIG. 17 depicts a perspective view of a method according to a preferredembodiment, which uses melted plastic as material in nozzles (42).

According to the embodiment shown, another nozzle (43) is provided forthe application of support material (44). The whole unit is therebymoved forward again on a conveyor belt (11). Since such a method formsan endless block, the finished part areas must be separated for removal,for example, by means of a hot wire saw (39).

The print heads (42, 43), which can generate individual drops of twodifferent materials, are moved in a layer application plane over thelayer body (35) and dispense the build material and support material(44) corresponding to the contour data issued by the computer. Thesupport material (44) should hereby ensure that at least the layerbody's (35) own weight can be supported on the conveyance unit (11).

An endlessly continuous method for a 3D printing process, during whichthe material is directly deposited with a print head (45), is depictedin FIG. 18.

A device used to accomplish this can be simplified for such a method.

In contrast to devices according to the state of technology, themovement of the device for layer positioning must not proceed rapidlybecause positioning runs with long paths are no longer needed. Asmentioned above, a consequence of such is that a discontinuous switchingdevice may also be used. Possible embodiments are depicted in FIG. 19and FIG. 20.

A powder feedstock (46) is provided on a conveyor belt (11).

In order to move one layer thickness after a coating process, the entireconveyor belt is moved in such a manner using the drive roller that theapplication plane approaches the drive roller as per the desired layerthickness. The torque required for this and the angle of rotation can beapplied using a lever (48) that is connected with a drive roller via anoverrunning clutch (47). The lever can be e.g. actuated by means of apneumatic cylinder (49). The layer thickness itself is then specified bythe travelling distance of the cylinder. This can be delimited by endstops.

Other gear stages (51) may make sense depending on the required torquemoments required. The layer thickness due to elasticity and slacknesscan be determined during commissioning and the desired target layerthickness can be set.

DESIGNATION LIST

1 Solidification unit

2 Spreader device

4 Building platform

5 Component

6 Vertical

7 Build height

8 Build chamber/Process chamber

9 Component (top from the build chamber)

10 Component (middle from the build chamber)

11 Component (lower from the build chamber)

12 Conveyor belt

13 Angle of repose

14 Angle of build plane relative to the conveyor belt

15 Solid delimitation wall

16 Run-off particulate material

17 End of device

18 Particulate material areas

19 Structures

20 Floor

21 Delimitation wall

22 Transfer conveyance means

23 Auxiliary structures

24 Robot

25 Guidance plate

26 Openings

27 Openings

28 Additional conveyor belt

29 Linked plates of the conveyor belt

30 Insertion unit

31 Rigid chain link

32 Magazine

33 Conveyor roller

34 Film layers

35 Model

36 Workpiece being run

37 Laser 1

38 Film rollers

39 Hot-wire saw

41 Job block

42 Nozzle for build material

43 Nozzle for support material

44 Support material

45 Print head

46 Powder feedstock

47 Overrunning clutch

48 Lever arm

49 Pneumatic cylinder

50 Frame

51 Chain-connected extended drive

The invention claimed is:
 1. A system for producing objects from a build material including a first material, the system comprising: i) at least one device for depositing the first material in layers; ii) at least one solidifying apparatus for selectively solidifying the first material; and iii) at least one means to convey the build material throughout a build-up process; wherein the means to convey includes a continuous solid surface for supporting the deposited layers.
 2. The system of claim 1, wherein the device for depositing the first material or the solidifying apparatus are moved on a coordinate system arranged at an angle to a reception plane of the continuous solid surface.
 3. The system of claim 1, wherein the first material is deposited on a reception plane angled relative to a horizontal plane, with an acute angle, a, wherein the acute angle is less than an angle of repose of the first material.
 4. The system of claim 3, wherein the device for depositing the first material is a spreader, the first material is a particulate material, and the spreader moves back and forth in a moving direction that is an x-direction or a y-direction of the reception plane, wherein the x-direction is parallel to the horizontal plane and the y-direction is angled relative to the horizontal plane.
 5. The system of claim 4, wherein the spreader deposits the particulate material while moving backward in the moving direction and while moving forward in the moving direction.
 6. The system of claim 5, wherein the system moves the means to convey a distance controlled by a measured height of the deposited layer.
 7. The system of claim 6, wherein the reception plane is angled relative to the continuous solid surface.
 8. The system of claim 7, wherein the means to convey moves in a horizontal direction, and the angle between the layer plane and the reception plane is less than the angle of repose of the particulate material.
 9. The system of claim 3, wherein the solidifying apparatus moves back and forth in a moving direction that is an x-direction or a y-direction of the reception plane, wherein the x-direction is parallel to the horizontal plane and the y-direction is angled relative to the horizontal plane.
 10. The system of claim 9, wherein the solidifying apparatus includes one or more printheads, a radiation source of a combination thereof.
 11. The system of claim 10, where the system includes two different solidifying apparatus.
 12. The system of claim 1, wherein the means to convey moves in a conveying direction that forms an acute angle, σ, to a horizontal plane.
 13. The system of claim 12, wherein the first material is a particulate material having an angle of repose, wherein the acute angle, σ, is less than or equal to the angle of repose.
 14. The system of claim 1, wherein the conveying direction is parallel to a horizontal plane.
 15. The system of claim 1, wherein the means to convey includes one or more conveyor belts.
 16. The system of claim 15, wherein the convey belt is a link conveyor belt.
 17. The system of claim 15, wherein the means to convey includes openings near an unpacking end of the conveyor belt or the system includes a gap between two sequential conveyor belts for removing loose particulate material.
 18. The systems of claim 15, wherein the system includes bordering surfaces on each side of the reception plane to stabilize the first material while the build material is conveyed.
 19. The system of claim 18, wherein each of the bordering surfaces includes an upright conveyor belt that is angled relative to the conveyor belt that conveys the build material, wherein the upright conveyor belts preferably moves synchronously with the conveyor belt moving the build material.
 20. The system of claim 15, wherein the conveyor belt has a surface on the edge to the deposited material which is parallel to the reception plane of the deposited material. 